如何将数据从TextForm保存到列表

Question

我想制作一个简单的应用程序，其中有Task类，该类显示在主页的Card类中。我有floatActionButton，通过它可以在AlertDialog中添加新任务，但是存在问题。当我想添加新任务时，会收到此消息 。

My HomePage class looks like this:

    class _HomeState extends State<Home> {

    List<Task> tasks = [
    Task(title: "Task4",text: "text of task 4"),
    Task(title: "Task5",text: "text of task 5"),
    Task(title: "Task6",text: "text of task 6"),
  ];

  var myController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.blueGrey[100],

      appBar: AppBar(
        backgroundColor: Colors.blueGrey[500],
        title: Text("Task Manager"),
        centerTitle: true,
      ),

      body: SingleChildScrollView(
        child: Column(
          children: tasks.map((task) => TaskCard(
            task: task,
            delete: (){
              setState(() {
                tasks.remove(task);
            });
          },
        )).toList(),
      ),
      ),

      floatingActionButton: FloatingActionButton(
        onPressed: (){
          return showDialog(
            context: context,
            builder: (BuildContext context){
              return AlertDialog(
                title: Text("New task"),
                content: TextFormField(
                  controller: myController,
                ),
                actions: <Widget>[
                  FlatButton(
                    child: Text("Submit"),
                    onPressed: (){
                      setState(() {
                        Task t = new Task();
                        t.title = myController.text;
                        tasks.add(t);
                      });
                      Navigator.of(context).pop();
                    },
                  )
                ],
              );
            }
          );
        },
        child: Icon(Icons.add),
        backgroundColor: Colors.blueGrey[500],
          ),
    
        );
      }

}

当然，我有Task.dart和TaskCard.dart。

任务类：

class Task {

  String title;
  String text;

  Task({this.text, this.title});
}

TaskCard类：

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'Task.dart';

class TaskCard extends StatelessWidget{

  final Task task;
  final Function delete;
  TaskCard({this.task, this.delete}); 

  @override
  Widget build(BuildContext context){
    return Card(
      margin: EdgeInsets.fromLTRB(10.0,10.0,10.0,5.0),
      color: Colors.blueGrey[200],
      child: Padding(
        padding: const EdgeInsets.all(10.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            Text(
              task.title,
              style: TextStyle(fontSize: 20.0, fontWeight: FontWeight.bold),
            ),
            SizedBox(height: 10.0,),
            Text(
              task.text,
              style: TextStyle(fontSize: 13.0),
            ),
            SizedBox(height: 10.0,),
            FlatButton.icon(
              onPressed: delete,
              label: Text("Done"),
              icon: Icon(Icons.done),
              color: Colors.blueGrey[300],
            )
          ],
        ),
      ),
    );
  }
}

Answer 1

问题似乎是因为您要设置新的Task的{​​{1}}。

title

..但未设置新的t.title = myController.text; 的{​​{1}}属性。

尝试将Task更改为此，然后查看问题是否仍然存在。

text